Minecraft Turtle: BuildPlane

-----------Written by Barnet-----------

function CheckSlot(Material)
  if turtle.getItemCount() ~= 0 then
    if turtle.getItemDetail().name == Material then
      return true
    else
      return false
    end
  else
    return false
  end
end

function Refill(Material)
  if CheckSlot(Material) == false then
    x = 1
    while x<17 do
      turtle.select(x)
      x=x+1
      if CheckSlot(Material) == true then
        x=17
      elseif x == 17 then
        turtle.select(1)
        print("Missing Material")
        error()
      end
    end
  end
end

function PlaceDown(Material)
  Refill(Material)
  if turtle.detectDown() == true and turtle.compareDown() == false then
    turtle.digDown()
  end
  turtle.placeDown()
end

function Forward()
  while turtle.forward() == false do
    if turtle.detect() == true then
      turtle.dig()
    else
      turtle.attack()
    end
  end
end

function BuildForward(a,Material)
  y=1
  while y<a do
    PlaceDown(Material)
    Forward()
    y=y+1
  end
end

function BuildRight(Material)
  PlaceDown(Material)
  turtle.turnRight()
  Forward()
  turtle.turnRight()
end

function BuildLeft(Material)
  PlaceDown(Material)
  turtle.turnLeft()
  Forward()
  turtle.turnLeft()
end

function BuildPlane(a,b,Material)
  c=0
  while c<b/2 do
    BuildForward(a,Material)
    BuildRight(Material)
    BuildForward(a,Material)
    BuildLeft(Material)
    c=c+1
  end
end

print()
print("Build a Plane")
print("---------------------------------------")
write("Length: ")
a = tonumber(read())
write("Width: ")
b = tonumber(read())
write("Material: ")
Material = read()
print("Building Plane...")
BuildPlane(a,b,Material)
print("Done!")